1. Field of the Invention
The present invention relates to a control method for deceleration of a vehicle and a system for the same. More particularly, the present invention relates to a control method for deceleration of a vehicle including a continuous valve lift apparatus and a system for the same.
2. Description of Related Art
In a recent vehicle, a controlling logic for stopping fuel injection (fuel cut-off) is in common use today for an engine control system in conditions that fuel injection is not required for enhancement of fuel consumption. The conditions may include a condition that a vehicle runs on a downhill road and an accelerator pedal is released, after that a throttle vale is controlled to be closed and fuel injection is stopped. In this case, pumping loss of an engine, as it is called an engine brake, is generated by closing the throttle valve, and thus vehicle speed is reduced.
However, rapid vehicle speed change induces bad effects to driving feeling and durability of a vehicle, so that throttle valve is not entirely closed. Thus, a small quantity of air keeps flowing into a cylinder. When fuel injection is stopped, combustion is not occurred, so that inflowing air may be supplied to a catalyst converter. In this case, the catalyst exposed to the air can be degraded, crack can be generated in the catalyst and purification of exhaust gas can be deteriorated rapidly.
The controlling logic for stopping fuel injection using air controlling may have trade off relationship between the pumping loss and degradation of the catalyst converter. However, if an engine equipped with a continuous variable valve lift (CVVL), which can control valve lift continuously, can be controlled effectively, the pumping loss can be reduced and inflowing air also can be controlled.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.